Thirlby will play Judge Cassandra Anderson, a psychically powered rookie Judge who teams with Judge Joe Dredd (Karl Urban) for training. Set in a dystopian future, the British comic book adaptation focuses on a police force given the power to act as judge, jury and executioner to whomsoever they perceive to be part of the criminal element.

In the 2000 A.D. comic book series (within which Judge Dredd is a recurring story), Anderson goes on to lead the city's Psi Division, maintaining an uneasy friendship with Dredd. Judge Dredd will be directed by Pete Travis with a script by Alex Garland. It was previously adapted into a film in 1995 with Sylvester Stallone in the lead. The character of Judge Anderson did not appear in that iteration of that franchise.